That Ubiquitous Sum: 1 + 2 + 3 + • • • + n

Stanley Bezuszka, Margaret Kenney

How the arithmetic series 1 + 2 + 3 + . . . + n is pervasive in mathematical contexts as a powerful problem-solving tool. Algebra students solve the problem with multiple approaches including geometric and creating general equations. Authors discuss the work of Cantor and Gauss in relation to the series.

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